The main objective of this proposal is to assess the regional diastolic elastic properties of the left ventricular (LV) myocardium, using a combined ultrasonic hemodynamic approach. The geometry of the ventricle will be defined using cross-sectiontal echocardiography (CSE), and a specially-designed articulated transducer arm to allow three-dimensional reconstruction of the LV. Simultaneous intracavitary pressure will be recorded using a catheter-tip transducer. The geometric and pressure data will be analyzed using the finite-element technique, solving for regional elastic properties using a modification of a computer program developed and used previously by the principal investigator. Specific aims to be achieved during the three years of requested funding are: 1) Validation of the approach for three-dimensional reconstruction of the LV chamber using excised hearts in vitro. 2) Recording simultaneous CSE and LV pressure data and deriving regional elastic properties of the LV in control state, closed-chest canines. 3) Deriving the regional elastic properties in closed-chest canines subjected to acute ischemia, and acute and subacute myocardial infarction. 4) Performing the analysis on patients undergoing clinically indicated cardiac catheterization for the study of known or suspected ischemic heart disease, including patients with known remote infarction.